Frame transmission scheme modification

ABSTRACT

In some embodiments, an apparatus is configured to wirelessly communicate with a base station using a first retransmission parameter in a first frame transmission scheme. In some embodiments, the apparatus is configured to determine a current performance metric and, based on the current performance metric, use a second, different retransmission parameter in a second frame transmission scheme for subsequent communications. In some embodiments, the retransmission parameter is a number of retransmissions or a number of hybrid automatic repeat request (HARQ) processes.

PRIORITY CLAIM

This application is a continuation of U.S. patent application Ser. No.15/878,331 filed on Jan. 23, 2018, now U.S. Pat. No. 10,412,679 issuedon Sep. 10, 2019, which is a continuation of U.S. patent applicationSer. No. 15/076,740 titled “Frame Transmission Scheme Modification” andfiled on Mar. 22, 2016, now U.S. Pat. No. 9,894,614 issued on Feb. 13,2018, which claims the benefit of U.S. Provisional Application No.62/141,109, filed on Mar. 31, 2015, U.S. Provisional Application No.62/158,279, filed on May 7, 2015, and U.S. Provisional Application No.62/172,661, filed on Jun. 8, 2015, all of which are hereby incorporatedby reference in their entirety as though fully and completely set forthherein.

The claims in the instant application are different than those of theparent application or other related applications. The Applicanttherefore rescinds any disclaimer of claim scope made in the parentapplication or any predecessor application in relation to the instantapplication. The Examiner is therefore advised that any such previousdisclaimer and the cited references that it was made to avoid, may needto be revisited. Further, any disclaimer made in the instant applicationshould not be read into or against the parent application or otherrelated applications.

TECHNICAL FIELD

The present application relates to wireless communication, includingenabling a mobile device to configure frame transmission parameters.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Further,wireless communication technology has evolved from voice-onlycommunications to also include the transmission of data, such asInternet and multimedia content.

Mobile electronic devices may take the form of smart phones or tabletsthat a user typically carries. Wearable devices (also referred to asaccessory devices) are a newer form of mobile electronic device, oneexample being smart watches. Typically, wearable devices have hadlimited wireless communications capabilities and were capable ofcommunicating only over wired interfaces or short-range point-to-pointtechnologies. Further, wearable devices typically have smaller batteriesthan larger portable devices, such as smart phones and tablets.

SUMMARY

Embodiments are presented herein of, inter alia, an accessory device,such as a smart watch, and associated methods for configuring a frametransmission scheme dynamically managing power consumption.

In some embodiments, an accessory device may perform an IP session witha base station. At a first time, communication between the accessorydevice and the base station may have a first performance metric and theaccessory device may implement a first frame transmission scheme. Thedevice may determine a current performance metric. Based on the currentperformance metric, the accessory device may modify the first frametransmission scheme.

In some embodiments, a mobile device is configured to prevent upcomingscheduled wireless transmission in response to detecting that a voltagecorresponding to battery output is below a particular threshold.

In some embodiments, a mobile device is configured to determine that thedevice is in a talking state and determine that a voltage correspondingto battery output is dropping below a threshold value at greater than athreshold frequency. In response, in these embodiments, the device isconfigured to perform a power reduction action. The action may includerequesting that other components reduce power usage and/or dynamicallyadjusting the number of hybrid automatic repeat request (HARQ) processesused to transmit audio frames.

The techniques described herein may be implemented in and/or used with anumber of different types of devices, including but not limited tocellular phones, portable media players, portable gaming devices, tabletcomputers, wearable computing devices, remote controls, wirelessspeakers, set top box devices, television systems, and computers.

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of the embodiments is consideredin conjunction with the following drawings.

FIG. 1 illustrates an example wireless communication system including anaccessory device;

FIG. 2 illustrates an example system where an accessory device canselectively either directly communicate with a cellular base station orutilize the cellular capabilities of an intermediate or proxy devicesuch as a smart phone;

FIG. 3 is a block diagram illustrating an example accessory device;

FIG. 4 is an exemplary coverage diagram;

FIG. 5 illustrates exemplary RLC segmentation;

FIG. 6 is a flowchart diagram illustrating a method whereby a audioframe bundles may be segmented;

FIG. 7 illustrates an exemplary retransmission scheme;

FIG. 8 is a flowchart diagram illustrating a method for performingdynamic HARQ process selection for audio frame transmission;

FIGS. 9-11 illustrate exemplary retransmission schemes;

FIG. 12 is a block diagram illustrating an accessory device thatincludes exemplary non-radio components, according to some embodiments;

FIG. 13A is a flowchart diagram illustrating a method for stoppingbaseband transmissions based on battery output level, according to someembodiments;

FIG. 13B is a flowchart diagram illustrating a method for re-schedulingstopped audio transmissions, according to some embodiments;

FIG. 14 is a flowchart diagram illustrating a method for requestingreductions in power consumption in a speech state, according to someembodiments;

FIG. 15 is a flowchart diagram illustrating a method for dynamicallymanaging HARQ processes based on battery output, according to someembodiments; and

FIG. 16 is a flowchart diagram illustrating a method for increasingpower to other components in non-talking speech states.

While the features described herein are susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

The term “configured to” is used herein to connote structure byindicating that the units/circuits/components include structure (e.g.,circuitry) that performs the task or tasks during operation. As such,the unit/circuit/component can be said to be configured to perform thetask even when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invokeinterpretation under 35 U.S.C. § 112(f) for that unit/circuit/component.

DETAILED DESCRIPTION

Terminology

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™,iPhone™), laptops, wearable devices (e.g. smart watch, smart glasses),PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Base Station—The term “Base Station” (also called “eNB”) has the fullbreadth of its ordinary meaning, and at least includes a wirelesscommunication station installed at a fixed location and used tocommunicate as part of a wireless cellular communication system.

Processing Element—refers to various elements or combinations ofelements. Processing elements include, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIG. 1—Wireless Communication System

FIG. 1 illustrates an example of a wireless cellular communicationsystem. It is noted that FIG. 1 represents one possibility among many,and that features of the present disclosure may be implemented in any ofvarious systems, as desired.

As shown, the exemplary wireless communication system includes acellular base station 102A, which communicates over a transmissionmedium with one or more wireless devices 106A, 106B, etc., as well asaccessory device 107. Wireless devices 106A, 106B, and 107 may be userdevices, which may be referred to herein as “user equipment” (UE) or UEdevices.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withthe UE devices 106A, 106B, and 107. The base station 102 may also beequipped to communicate with a network 100 (e.g., a core network of acellular service provider, a telecommunication network such as a publicswitched telephone network (PSTN), and/or the Internet, among variouspossibilities). Thus, the base station 102 may facilitate communicationbetween the UE devices 106 and 107 and/or between the UE devices 106/107and the network 100. In other implementations, base station 102 can beconfigured to provide communications over one or more other wirelesstechnologies, such as an access point supporting one or more WLANprotocols, such as 802.11 a, b, g, n, ac, ad, and/or ax, or LTE in anunlicensed band (LAA).

The communication area (or coverage area) of the base station 102 may bereferred to as a “cell.” The base station 102 and the UEs 106/107 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs) or wireless communicationtechnologies, such as GSM, UMTS (WCDMA, TDS-CDMA), LTE, LTE-Advanced(LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD),Wi-Fi, WiMAX etc.

Base station 102 and other similar base stations (not shown) operatingaccording to one or more cellular communication technologies may thus beprovided as a network of cells, which may provide continuous or nearlycontinuous overlapping service to UE devices 106A-N and 107 and similardevices over a wide geographic area via one or more cellularcommunication technologies.

Note that at least in some instances a UE device 106/107 may be capableof communicating using any of a plurality of wireless communicationtechnologies. For example, a UE device 106/107 might be configured tocommunicate using one or more of GSM, UMTS, CDMA2000, WiMAX, LTE, LTE-A,WLAN, Bluetooth, one or more global navigational satellite systems(GNSS, e.g., GPS or GLONASS), one and/or more mobile televisionbroadcasting standards (e.g., ATSC-M/H), etc. Other combinations ofwireless communication technologies (including more than two wirelesscommunication technologies) are also possible. Likewise, in someinstances a UE device 106/107 may be configured to communicate usingonly a single wireless communication technology.

The UEs 106A and 106B are typically handheld devices such as smartphones or tablets, but may be any of various types of device withcellular communications capability. The UE 106B may be configured tocommunicate with the UE device 107, which may be referred to as anaccessory device 107. The accessory device 107 may be any of varioustypes of devices, typically a wearable device that has a smaller formfactor, and may have limited battery, output power and/or communicationsabilities relative to UEs 106. As one common example, the UE 106B may bea smart phone carried by a user, and the accessory device 107 may be asmart watch worn by that same user. The UE 106B and the accessory device107 may communicate using any of various short range communicationprotocols, such as Bluetooth.

The accessory device 107 includes cellular communication capability andhence is able to directly communicate with cellular base station 102.However, since the accessory device 107 is possibly one or more ofcommunication, output power and/or battery limited, the accessory device107 may in some instances selectively utilize the UE 106B as a proxy forcommunication purposes with the base station 102 and hence to thenetwork 100. In other words, the accessory device 107 may selectivelyuse the cellular communication capabilities of the UE 106B to conductits cellular communications. The limitation on communication abilitiesof the accessory device 107 can be permanent, e.g., due to limitationsin output power or the radio access technologies (RATs) supported, ortemporary, e.g., dues to conditions such as current battery status,inability to access a network, or poor reception.

FIG. 2 illustrates an example accessory device 107 in communication withbase station 102. The accessory device 107 may be a wearable device suchas a smart watch. The accessory device 107 may comprise cellularcommunication capability and be capable of directly communicating withthe base station 102 as shown. When the accessory device 107 isconfigured to directly communicate with the base station, the accessorydevice may be said to be in “autonomous mode.”

The accessory device 107 may also be capable of communicating withanother device (e.g., UE 106), referred to as a proxy device orintermediate device, using a short range communications protocol, andmay then use the cellular functionality of this proxy device forcommunicating cellular voice/data with the base station 102. In otherwords, the accessory device 107 may provide voice/data packets intendedfor the base station 102 over the short range link to the UE 106, andthe UE 106 may use its cellular functionality to transmit (or relay)this voice/data to the base station on behalf of the accessory device107. Similarly, the voice/data packets transmitted by the base stationand intended for the accessory device 107 may be received by thecellular functionality of the UE 106 and then may be relayed over theshort range link to the accessory device. As noted above, the UE 106 maybe a mobile phone, a tablet, or any other type of hand-held device, amedia player, a computer, a laptop or virtually any type of wirelessdevice. When the accessory device 107 is configured to indirectlycommunicate with the base station using the cellular functionality of anintermediate or proxy device, the accessory device may be said to be in“relay mode.”

The accessory device 107 may include a processor that is configured toexecute program instructions stored in memory. The accessory device 107may perform any of the method embodiments described herein by executingsuch stored instructions. Alternatively, or in addition, the accessorydevice 107 may include a programmable hardware element such as an FPGA(field-programmable gate array), or other circuitry, that is configuredto perform any of the method embodiments described herein, or anyportion of any of the method embodiments described herein.

The accessory device 107 may include one or more antennas forcommunicating using two or more wireless communication protocols orradio access technologies. In some embodiments, the UE device 106 mightbe configured to communicate using a single shared radio. The sharedradio may couple to a single antenna, or may couple to multiple antennas(e.g., for MIMO) for performing wireless communications. Alternatively,the UE device 106 may include two or more radios. For example, the UE106 might include a shared radio for communicating using either of LTE(or LTE-Advanced) or Bluetooth, and separate radios for communicatingusing each of LTE-Advanced and Bluetooth. Other configurations are alsopossible.

The accessory device 107 may be any of various types of devices that, insome embodiments, has a smaller form factor relative to a conventionalsmart phone, and may have one or more of limited communicationcapabilities, limited output power, or limited battery life relative toa conventional smart phone. As noted above, in some embodiments, theaccessory device 107 is a smart watch or other type of wearable device.As another example, the accessory device 107 may be a tablet device,such as an iPad, with WiFi capabilities (and possibly limited or nocellular communication capabilities) which is not currently near a WiFihotspot and hence is not currently able to communicate over WiFi withthe Internet. Thus, the term “accessory device” refers to any of varioustypes of devices that in some instances have limited or reducedcommunication capabilities and hence may selectively andopportunistically utilize the UE 106 as a proxy for communicationpurposes for one or more applications and/or RATs. When the UE 106 iscapable of being used by the accessory device 107 as a proxy, the UE 106may be referred to as a companion device to the accessory device 107.

FIG. 3—Example Block Diagram of an Accessory Device

FIG. 3 illustrates one possible block diagram of an accessory device107. As shown, the accessory device 107 may include a system on chip(SOC) 300, which may include portions for various purposes. For example,as shown, the SOC 300 may include processor(s) 302 which may executeprogram instructions for the accessory device 107, and display circuitry304 which may perform graphics processing and provide display signals tothe display 360. The processor(s) 302 may also be coupled to memorymanagement unit (MMU) 340, which may be configured to receive addressesfrom the processor(s) 302 and translate those addresses to locations inmemory (e.g., memory 306, read only memory (ROM) 350, Flash memory 310).The MMU 340 may be configured to perform memory protection and pagetable translation or set up. In some embodiments, the MMU 340 may beincluded as a portion of the processor(s) 302.

The accessory device 107 may also include other circuits or devices,such as the display circuitry 304, radio 330, connector I/F 320, and/ordisplay 340.

In the embodiment shown, ROM 350 may include a bootloader, which may beexecuted by the processor(s) 302 during boot up or initialization. Asalso shown, the SOC 300 may be coupled to various other circuits of theaccessory device 107. For example, the accessory device 107 may includevarious types of memory, a connector interface 320 (e.g., for couplingto a computer system), the display 360, and wireless communicationcircuitry (e.g., for communication using LTE, CDMA2000, Bluetooth, WiFi,NFC, GPS, etc.).

The accessory device 107 may include at least one antenna, and in someembodiments multiple antennas, for performing wireless communicationwith base stations and/or other devices. For example, the accessorydevice 107 may use antenna 335 to perform the wireless communication. Asnoted above, the UE may in some embodiments be configured to communicatewirelessly using a plurality of wireless communication standards orradio access technologies (RATs).

As described herein, the accessory device 107 may include hardware andsoftware components for implementing methods according to embodiments ofthis disclosure. The processor 302 of the accessory device 107 may beconfigured to implement part or all of the methods described herein,e.g., by executing program instructions stored on a memory medium (e.g.,a non-transitory computer-readable memory medium). In other embodiments,processor 302 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit).

It is noted that the UEs 106A and 106B shown in FIG. 1 may have asimilar architecture to that described above.

Audio Frame Bundling and Segmentation

Audio frame delay may be one of the most important indicators to measurevoice over IP (e.g., voice over LTE (VoLTE)) quality. In someembodiments, audio frame delay may be specified according to thefollowing formula:T_delay=T_bundling+T_wait+T_transmission

Generally, T_delay should be less than or equal to an audio delay budgetwhich is imposed by the network. For example, many networks may use adelay budget of 80 ms, although other values are envisioned.

T_bundling is the audio delay caused by bundling multiple audio framesinto an audio bundle for transmission. Generally, T_bundling may bedetermined using:T_bundling=(n−1)T

where T is the audio sampling rate (e.g., 20 ms) and n is the number ofaudio frames which are bundled into an audio bundle. For example, using20 ms:

-   -   1 audio frame in a bundle, T_bundling=0;    -   2 audio frames in a bundle, T_bundling=20 ms;    -   3 audio frames in a bundle, T_bundling=40 ms;    -   4 audio frames in bundle, T_bundling=60 ms.

T_wait may be the time an audio bundle has to wait for an available HARQprocess to start transmission.

Finally, T_transmission may be the time an audio bundle takes totransmit successfully (e.g., to a base station or eNodeB). Thistransmission time may include time for HARQ retransmissions, which maydepend heavily on current radio conditions and can vary by a largemargin. Accordingly, in some embodiments, in order to meet the audiodelay budget (e.g., 80 ms) for different audio bundling schemes, theT_transmission may have a limit as well:

-   -   1-audio bundle, T_transmission<=80 ms;    -   2-audio bundle, T_transmission<=60 ms;    -   3-audio bundle, T_transmission<=40 ms;    -   4-audio bundle, T_transmission<=20 ms.

FIG. 4 illustrates an exemplary cell coverage diagram. In someembodiments, the UE 106 may include a plurality of antennas (e.g., twoantennas), may not have an RF sensitivity issue, and/or may have enoughbattery power for contiguous TX at peak power for a long period of time.As a result, in cell coverage B+C, the UE 106 may be within an uplinkbudget (e.g., a voice over LTE (VoLTE) uplink budget). However, in cellcoverage A may involve far cell conditions. In one embodiment, the UEmay receive >−80 dBm power from the base station 102 in coverage C, >−90dBm in coverage B, and <−90 dBm in coverage A.

In some embodiments, accessory device 107 may include a single antenna,incur some RF sensitivity degradation (e.g., 10 dB RF sensitivitydegradation) relative to the UE 106, and may include a battery that cansupport at least 4/8 duty cycle or contiguous TX at peak power forseconds. Similar to UE 106, the accessory device 107 may be within anuplink budget with cell coverage C. However, in cell coverage B or A andbeyond, far cell conditions may apply.

In far cell conditions, or range limited devices, such as the accessorydevice 107, there may be two methods to extend the link or audio delaybudget (although more are also envisioned):

1) reduce payload for transmission, which is the size of an audiobundle; or

2) increase number of HARQ retransmissions, which is limited by theT_transmission limit mentioned above.

For a fixed audio bundle size, RLC (radio link control) segmentation maybe used to extend link budget without increasing the number of HARQretransmissions to avoid exceeding the audio delay budget. RLCsegmentation, which uses the RLC protocol to segment a RLC PDU (packetdata unit) to several RLC segment PDUs, may involve transmitting all RLCsegments using multiple HARQ processes in parallel, instead of one HARQprocess for an entire audio bundle. This method may effectively decreasepayload size and thus extend link budget.

As shown in FIG. 5, when using RLC segmentation, two audio framesreceived per 40 ms may be segmented as RLC SDUs into a maximum of fourRLC segments and fill in the four HARQ processes, and with each HARQprocess retransmitting 2 to 3 times, this leads to contiguoustransmission over the entire 40 ms period.

While RLC segmentation allows higher total energy accumulation within adelay budget, it involves extra overhead due to extra RLC and MACheaders resulting in a higher data rate, thus lower accumulated energyper payload bit. Additionally, because an RLC PDU (the original audiobundle) is segmented into several RLC segment PDUs for transmission, thereceiver (e.g., the base station) may have to successfully receive allRLC segments and then re-assemble them back into the original audiobundle without any of the RLC segments being lost. Thus, if any segmentis lost, then even if all the other segments are received correctly, theentire audio bundle may still be lost. Thus, RLC segmentation can leadto excessive queuing delay due to network device(s) having to reassembleall segments back to one complete RLC PDU (packet data unit). Forexample, if one segment is missing for a long period of time, it couldlead to audio frame build-up delay and get dropped, resulting in thelink budget being limited.

Moreover, if P is the block error rate for a RLC segment, and if onebundle is segmented to two segments:(1−P)*(1−P)=1−n%

where n is the target block error rate (BLER) that may be configured bythe network and P is the BLER target for each segment. According to thisrelationship, as RLC segments increase, the P value decreases. Forexample, 1% may be the typical VoLTE BLER configured by the network.Accordingly, for two segments, P=0.5%, which means each RLC segment BLERtarget has to be 0.5% in order to achieve the original audio bundle BLERof 1%. For three RLC segments, each RLC segment BLER target may have tobe 0.3%, in order to achieve original audio bundle BLER 1%. As a result,there is link budget loss for RLC segmentation. However, this loss maybe avoided according to some embodiments described herein. Inparticular, more efficient accumulation of energy per payload bit may beattained than through RLC segmentation, which may enhance uplink budgetwith minimal or no changes on the network side.

As an example, an exemplary network configuration may specify a codec of12.65 Kbps, and two audio frames may be bundled into an audio bundlethat is transmitted every 40 ms. In this example, the audio bundle sizemay be (253 bits+40 bites ROHC/PDCP header)*2+16 bits RLC/MAC header=586bits+16 bits RLC/MAC header=602 bits. Accordingly, if the networkprovides an uplink grant transport block size (TBS) that is greater thanor equal to 602 bits, then this audio bundle can be transmitted in oneTTI (transmission time interval). However, if the uplink grant TBS isless than 602 bits (e.g., 301 bits), then the transmitting device cannottransmit the entire audio bundle in one TTI.

Accordingly, to avoid RLC segmentation, the audio frames may beseparated at the audio bundle level instead of at RLC PDU level in someembodiments. Following the example above, where the uplink grant size is301 bits and the audio bundle has two audio frames, the audio bundle maybe reduced to a single audio frame, thus splitting the audio bundle intotwo transmissions, each matching the uplink grant size and avoiding RLCsegmentation. Thus, RLC segmentation is no longer necessary, and if anyone of the two audio bundles is lost, the other one still can be decodedand processed as an independent audio bundle. A similar procedure may beapplied to audio bundles having more audio frames. For example, an audiobundle having three audio frames may be segmented into three independentaudio bundles, each including one audio frame. For an audio bundlehaving four audio frames, it may be segmented into four independentaudio bundles, each includes one audio frame, or two independent audiobundles, each including two audio frames, as desired. Other bundles andsegmentations are envisioned.

This procedure can also be extended to the audio frame itself. Forexample, if an audio frame is coded by 12.65 kbps, it may have a size of253 bits. This audio bundle can be segmented and re-packed into twoaudio frames each with a codec rate 6.6 kbps, having a size of 132 bits.Accordingly, these two independent audio bundles may be transmitted tothe network, instead of two RLC segments.

FIG. 6—Audio Frame Bundle Segmentation

FIG. 6 is a flowchart diagram illustrating a method for performing audioframe bundle segmentation. The method may be performed by an accessorydevice (such as accessory device 107) and/or a UE device (such as UE106), e.g., using the systems and methods discussed above. Moregenerally, the method shown in FIG. 6 may be used in conjunction withany of the systems or devices shown in the above Figures, among otherdevices. In various embodiments, some of the method elements shown maybe performed concurrently, in a different order than shown, or may beomitted. Note also that additional method elements may also be performedas desired. The method may be performed as follows.

In 602, device may perform a real-time IP session, e.g., including voiceor video over IP session, such as VoLTE. For the remainder of thisdescription, the session may be referred to as a voice over IP sessioninvolving audio frames and audio bundles, but it may be extended tovideo frames and video bundles or any transmissions associated with areal-time IP session or application, etc.

In 604, the device may determine or receive an uplink grant size forVoIP session. For example, the device may receive an uplink granttransport block size that specifies a number of bits for audio bundlesof the VoIP session.

In 606, the device may compare the uplink grant size to the audio bundlesize of the present audio configuration. The audio bundle size may bebased on the audio codec in use, the number of audio frames in the audiobundle, etc. specified by the audio configuration.

In 608, in response to the uplink grant size being less than the audiobundle size, the device may modify the audio configuration to reduce theaudio bundle size to less than or equal to the uplink grant size, e.g.,to avoid RLC segmentation. For example, if the present audio bundle sizeis 602 bits and the uplink grant size is 301 bits, and the number ofaudio frames per bundle is greater than one (e.g., two), then the numberof audio frames per bundle may be reduced, e.g., in this example to oneaudio frame per bundle. Similarly, audio bundles of three audio framesmay be split into single audio frames per bundle. Audio bundles of fouraudio frames may be split into single audio framer per bundle or twoframes per bundle, depending on the ratio of the uplink grant size tothe audio bundle size (e.g., two frames per bundle may be used, ifpossible).

However, if the audio frames per bundle is already one, it may beresampled using a different codec rate. For example, if an audio frameis coded by 12.65 kbps, it may have a size of 253 bits. This audiobundle can be segmented and re-packed into two audio frames each with acodec rate 6.6 kbps, having a size of 132 bits. Thus, even single audioframes can be reduced in size via a codec rate change (among otherpossibilities) rather than using RLC segmentation.

Dynamically Enhancing Uplink Budget

Referring back to FIG. 4, in cell coverage A, TTI (time transmissioninterval) bundling (e.g., 4-TTI-B) may be enabled for the UE. In someembodiments, it may be typical to implement RLC segmentation beyond cellcoverage A. Similar to UE 106, the accessory device 107 may be within anuplink budget with cell coverage C. However, in cell coverage B, TTIbundling (e.g., 4 TTI-B) may be enabled. In cell coverage A and beyondA, various embodiments described herein may be particularly useful.

In some implementations (e.g., for LTE VoLTE) 4-TTI bundling, HARQ(hybrid automatic repeat request) retransmission, and/or RLC (radio linkcontrol) segmentation may be used to extend uplink budget whileexperiencing weak cell conditions (e.g., conditions associated with cellcoverage A in FIG. 4).

In some embodiments, after TTI bundling is enabled by the network afterdetecting weak cell radio conditions, the audio codec rate (e.g., of theaccessory device 107, although some embodiments may also apply to the UE106) can be reduced to a minimum value such as a lowest WB-AMR (widebandadaptive multi-rate) rate of 6.6 kbps, which utilizes the minimum uplinkgrant (MCS (modulation and coding scheme)+number of PRBs (physicalresource blocks)) to allow only one MAC (media access control) PDUwithout RLC segmentation, similar to discussions above. For example,audio frame(s) may be bundled to within one MAC PDU, thereby avoidingRLC segmentation. This reduction in the audio codec rate may allow oneMAC PDU in one HARQ process (such as HARQ process 0) to be transmittedfour times in one TTI bundle, and the TTI bundle can be retransmitted Ntimes through HARQ, depending on the retransmissions allowed (e.g., fourtimes for 4-TTI-B).

In some embodiments, the accessory device 107 (and/or the UE 106) maymeasure the UL block error rate (BLER) by counting ACK/NACKs on HARQprocess 0. If the BLER is more than a threshold (e.g., 10%), the device107 may transmit an uplink buffer status message to indicate to thenetwork that there are more buffers for a given MAC PDU pending fortransmission. Accordingly, the network may allocate an uplink grant foranother not-yet-used HARQ process, and the device 107 may start totransmit the same MAC PDU on the not-yet-used HARQ process (such as HARQprocess 1). This effectively doubles the number of transmissions for theMAC PDU.

In some embodiments, the accessory device 107 (and/or the UE 106) maymeasure joint uplink BLER by counting ACK/NACKs on both HARQ processes 0and 1. Similar to the above, if the BLER is more than a threshold (e.g.,10%), the device 107 may transmit an uplink buffer status message toindicate to the network that there are more buffers for a given MAC PDUpending for transmission. Again, the network may allocate an uplinkgrant, and the device may start to transmit the same MAC PDU on anothernot-yet-used HARQ process (such as HARQ 2). This effectively generatesthree times the number of transmissions for the MAC PDU.

In some embodiments, the accessory device 107 (and/or the UE 106) maymeasure joint uplink BLER by counting ACK/NACKs on HARQ processes 0, 1,and 2. If the BLER is more than a threshold (e.g., 10%), the device 107may send an UL buffer status message to indicate to the network thatthere are more buffers for a given MAC PDU pending for transmission.Again, the network may allocate an uplink grant, and the device 107 maystart to transmit the same MAC PDU on another not-yet-used HARQ process(such as HARQ process 3). This effectively generates four times numberof transmissions for the MAC PDU.

In some embodiments, whenever the above mentioned joint UL BLER is lessthan a threshold (e.g., 5%), the device may stop transmitting a givenMAC PDU on a HARQ process. For example, the device may remove HARQprocesses from the joint HARQ group until there is only one left,effectively reducing the number of maximum possible retransmissionsprogressively down to only one HARQ active process.

These described embodiments may not need changes on the network side. Inparticular, by transmitting the same MAC PDU on multiple HARQ processes,energy accumulation may be increased per payload bit from the networkside, thereby increasing the chances of correctly decoding payload data.Moreover, since the RLC PDU has sequence number in it, RLC can discardthe duplicates one if more than one HARQ processes has correctly decodedthe MAC PDU.

In some embodiments, to further increase the network decodingefficiency, the network can combine received contents from the abovementioned multiple HARQ processes, which may effectively produce thesame as 4 ms TTI bundling, 8 ms TTI bundling, 12 ms TTI bundling, and/or16 ms TTI bundling, as each HARQ process is added. In some embodiments,even without TTI bundling enabled by the network, a similar approach canalso be applied to embodiments in which 8 UL HARQ processes are used.

In the example of FIG. 7, the accessory device 107 (and/or the UE 106)receives two audio frames per 40 ms interval to be transmitted, with adelay budget of 80 ms and with 4-TTI-B enabled. In FIG. 7, each number 0through 3 represents a HARQ process with a total of four HARQ processes.Additionally, the HARQ retransmission count may be set to four so thatone HARQ process can transmit the same PDU 5 times within the 80 msdelay budget, as shown in the diagram. After enabling 4-TTI-B, in each80 ms period, two MAC PDUs (701 and 703) are transmitted starting inadjacent 40 ms intervals, each occupying one HARQ process (0 and 2,respectively), and each including two bundled audio frames. Accordingly,in this example, there are two HARQ processes that are not used (1 and3). Thus, the device may send one MAC PDU per 40 ms to the network. Ifeach HARQ process (0 and 2 in this example) retransmits four times, thenwithin an 80 ms period, the device can transmit two MAC PDUs, each witha number of transmissions of 4×5=20.

However, if twenty transmissions of a MAC PDU is still not enough forthe network to accumulate sufficient energy per payload bit foracceptable reception quality, in some embodiments, the device cantransmit the MAC PDU on another not-yet-used HARQ process (process 0 andprocess 1 for the 701 and 702 MAC PDUs and process 2 and process 3 forthe 703 and 704 MAC PDUs, each set corresponding to a correspondingaudio frame bundle). This may effectively double the number oftransmission for each MAC PDU. Accordingly, in an 80 ms period, thedevice can transmit two MAC PDUs, each with number of transmissions of2×4×5=40.

FIG. 8—Dynamic HARQ Process Selection for Audio Frame Transmission

FIG. 8 is a flowchart diagram illustrating a method for performingdynamic HARQ process selection for audio frame transmission. The methodmay be performed by an accessory device (such as accessory device 107)and/or a UE device (such as UE 106), e.g., using the systems and methodsdiscussed above. More generally, the method shown in FIG. 8 may be usedin conjunction with any of the systems or devices shown in the aboveFigures, among other devices. In various embodiments, some of the methodelements shown may be performed concurrently, in a different order thanshown, or may be omitted. Note also that additional method elements mayalso be performed as desired. The method may be performed as follows.

In 802, a device may perform a real-time IP session, e.g., includingvoice or video over IP session, such as VoLTE. In 802, the device maycommunicate with a base station and have a first performance metric(e.g., signal to noise ratio (SNR), block error rate (BLER), receivedsignal strength indication (RSSI), reference signal received power(RSRP), reference signal received quality (RSRQ), and/or any othermetric or combination of metrics). The device may transmit frames (e.g.,audio frames) for the session using a first audio codec rate, a firstMAC PDU size, a first frame bundling scheme, a first retransmissionscheme, and/or a first one or more HARQ processes. In some embodiments,the first performance metric may be above a performance metricthreshold. When above the threshold, retransmission and/or HARQ may notbe performed (e.g., if coverage corresponds to C, discussed above).Alternatively, a first retransmission scheme and/or one or more HARQprocesses may be used in 702 (e.g., if coverage corresponds to B or A,discussed above).

In 804, the device may determine a current performance metric (which maybe referred to as a “second performance metric”).

In 806, based on current performance, the device may change how framesare transmitted. For example, in response to current performance fallingbelow an acceptable rate (e.g., the second performance metric fallingbelow the performance metric threshold), the device may modify one ormore activities to attempt to ensure proper delivery of the frames(e.g., the audio frames) for the session. For example, the device maylower the audio codec rate, e.g., in order to allow each frame or framebundle to fit within a single MAC PDU rather than using RLCsegmentation. Additionally, or alternatively, a second or differentretransmission scheme may be used (e.g., 4-TTI-B, 2-TTI-B, etc.).Further, additional available HARQ processes may be used to increaseretransmissions of audio frames or audio frame bundles. The MAC PDU sizemay also be modified, if desired.

In one embodiment, the device may measure a BLER of transmitted framesor bundles, and if it exceeds a threshold, additional retransmissions orHARQ processes may be used to ensure proper reception of the frames.

In some embodiments, 804 and 806 may be repeated throughout the session.While performance remains unacceptable (e.g., falling below theperformance metric threshold), additional retransmissions and/or HARQprocesses may be used (among other possibilities). If performanceimproves, these changes may be reversed, e.g., increasing audio codecrate, decreasing retransmissions, decreasing HARQ process use, etc.These changes may result in better battery utilization and/or betteraudio quality, depending on the changes.

Dynamic Audio Frame Bundling

In some embodiments, accumulating more energy per payload bit in an IPsession (e.g., a VoLTE) delay budget may be beneficial in increasinguplink budget.

As discussed above, in some embodiments, the payload size may bereduced. For example, the audio payload may be reduced, by using a loweraudio codec rate. As a specific example, reducing the rate from AMR-WB12.65 kbps down to AMR-WB-6.6 kbps may provide approximately a 3 dB gainin link budget associated with a 50% rate decrease.

Additionally or alternatively, the protocol header overhead may beminimized. For example, fixed-sized UDP/IP/RTP, PDCP/RLC/MAC headeroverhead (7 bytes) over a bundle of multiple audio frames may beimplemented instead of over one single audio frame (e.g., 1 audio frameper 20 ms, 2 audio frames in a bundle per 40 ms, 3 audio frames in abundle per 60 ms), which may provide 0.6 dB gain in link budgetassociated with the header overhead reduction.

One audio bundle may be segmented into multiple RLC segment PDUs thatare transmitted over multiple HARQ processes instead of one HARQprocess. However, as discussed above, RLC segmentation may increaseRLC/MAC header overhead per segment, thus increasing overall payloadsize. Additionally, more segments may also delay RLC PDU reassembly andlead to excessive queuing delay, thus potentially causing discards ofaudio frames.

Instead of segmentation, the same RLC PDU can be retransmitted multipletimes from the RLC level such that the full RLC PDU is retransmitted asa MAC PDU over each one of multiple HARQ processes. This technique maynot cause delay on RLC reassembly and may effectively increase thenumber of retransmissions that can be performed per audio payload.

Improvements may also be implemented by increasing the number ofretransmissions for an audio frame within the delay budget (e.g., theVoLTE delay budget). The delay budget may be a network parameter. As oneexample, since the PDCP (packet data convergence protocol) discard timercan often be set to 100 ms, and the maximum HARQ transmission number canoften be set to 5, the delay budget between the device and the basestation (e.g., the eNodeB) may be 80 ms (5 HARQ retransmissions×4 HARQprocesses×4-TTI bundling).

For the 4-TTI-B case using an AMR-WB 6.6 kbps codec, one audio framewith 132 bits per 20 ms can be retransmitted a maximum of 20 times andmay have the best link budget. In the case of one audio frame per 20 ms,using four HARQ processes out of four, the device can transmit fouraudio frames in 80 ms, each frame being retransmitted a maximum of 20times. In the case of two audio frames as a bundle per 40 ms, using twoHARQ processes out of four, the device can transmit two bundles in 80ms, each bundle being retransmitted a maximum of 20 times. In the caseof three audio frames as a bundle per 60 ms, using two HARQ processesout of four, the device can transmit two bundles in 80 ms, each bundlebeing retransmitted a maximum of 20 times.

For the 2-TTI-B case using an AMR-WB 6.6 kbps codec, one audio framewith 132 bits per 20 ms can be retransmitted a maximum of 20 times andmay have the best link budget. In the case of one audio frame per 20 ms,using four HARQ processes out of four, the device can transmit fouraudio frames in 80 ms, each frame retransmitting a maximum of 20 times.In the case of two audio frames as a bundle per 40 ms, using two HARQprocesses out of four, the device can transmit two bundles in 80 ms,each bundle retransmitting a maximum of 20 times. In the case of threeaudio frames as a bundle per 60 ms, using two HARQ processes out offour, the device can transmit two bundles in 80 ms, each bundleretransmitting a maximum of 20 times.

For a case involving no TTI bundling using an AMR-WB 6.6 kbps codec, oneaudio frame with 132 bits per 20 ms can be retransmitted a maximum of 10times, and has the best link budget. Each audio frame of the total fouraudio frames may be retransmitted in 80 ms on the other un-used fourHARQ processes, so one audio frame with 132 bits per 20 ms can beretransmitted a maximum of 20 times and may have the best link budget.In the case of one audio frame per 20 ms, using four HARQ processes outof eight, the device can transmit four audio frames in 80 ms, each frameretransmitting a maximum of 10 times. In the case of two audio frames asa bundle per 40 ms, using two HARQ processes out of eight, the devicecan transmit two bundles in 80 ms, each bundle retransmitting a maximumof 10 times. In the case of three audio frames as a bundle per 60 ms,using two HARQ processes out of eight, the device can transmit twobundles in 80 ms, each bundle retransmitting a maximum of 10 times.

FIG. 9 illustrates 4-TTI-B with audio frame periodicity of 20 ms, 40 ms,and 60 ms. For an audio frame periodicity of 20 ms, FIG. 9 illustratesone audio frame with 132 bits in a MAC PDU. Accordingly, four differentMAC PDUs may be transmitted in 80 ms, each MAC PDU in a different HARQprocess, each of which can retransmit a maximum of 20 times (4 TTIbundling×5 transmissions). In particular, audio frames 901, 902, 903,and 904 are transmitted using HARQ processes 0, 1, 2, and 3. Audio frame905 represents the end of the delay budget of 80 ms for audio frame 901and the point where HARQ process 0 is reused for a new audio frame.

For an audio frame periodicity of 40 ms, FIG. 9 illustrates two audioframes with 264 bits in a MAC PDU. Accordingly, two different MAC PDUsmay be transmitted in 80 ms, each MAC PDU in a different HARQ process,each of which can retransmit a maximum of 20 times. In particular, audioframe bundles 911, 912, 913, and 914 are transmitted using HARQprocesses 0, 2, 1, and 3, respectively.

For an audio frame periodicity of 60 ms, FIG. 9 illustrates three audioframes with 396 bits in a MAC PDU. Accordingly, two different MAC PDUsmay be transmitted in 80 ms, each MAC PDU in a different HARQ process,each of which can retransmit a maximum of 20 times. In particular, audioframe bundles 921, 922, 923, and 924 are transmitted using HARQprocesses 0, 3, 2, and 1, respectively.

FIG. 10 illustrates 2-TTI-B with audio frame periodicity of 20 ms, 40ms, and 60 ms. For an audio frame periodicity of 20 ms, FIG. 10illustrates a single audio frame with 132 bits in one MAC PDU.Accordingly, four MAC PDUs may be transmitted in 80 ms, each MAC PDU ina different HARQ process, each of which can retransmit a maximum of 20times (2-TTI bundling×10 transmissions). In particular, audio frames1001, 1002, 1003, and 1004 are transmitted using HARQ processes 0, 2, 1,and 3, respectively.

For an audio frame periodicity of 40 ms, FIG. 10 illustrates two audioframes with 264 bits in one MAC PDU. Accordingly, two MAC PDUs may betransmitted in 80 ms, each MAC PDU in a different HARQ process, each ofwhich can retransmit a maximum of 20 times (2-TTI bundling×10transmissions). In particular, audio frame bundles 1011, 1012, and 1013are transmitted using HARQ processes 0, 1, and 2, respectively.

For an audio frame periodicity of 60 ms, FIG. 10 illustrates three audioframes with 396 bits in one MAC PDU. Accordingly, two MAC PDUs may betransmitted in 80 ms, each MAC PDU in a different HARQ process, each ofwhich can retransmit a maximum of 20 times. In particular, audio framebundles 1021 and 1022 are transmitted using HARQ processes 0 and 3,respectively.

FIG. 11 illustrates 1TTI with 20 ms, 40 ms, and 60 ms audio frameperiodicity. For an audio frame periodicity of 20 ms, FIG. 11illustrates a single audio frame with 132 bits in a MAC PDU.Accordingly, four MAC PDUs may be transmitted in 80 ms, each MAC PDU ina different HARQ process, each of which can retransmit a maximum of 10times. In this example, audio frames 1101, 1102, 1103, 1104, 1105, 1106,1107, and 1108 are transmitted using HARQ processes 0, 4, 1, 5, 2, 5, 3,and 7, respectively.

For an audio frame periodicity of 40 ms, FIG. 11 illustrates two audioframes with 264 bits in a MAC PDU. Accordingly, two MAC PDUs may betransmitted in 80 ms, each MAC PDU in a different HARQ process, each ofwhich can retransmit a maximum of 10 times. In particular, audio framebundles 1111, 1112, 1113, and 1114 are transmitted using HARQ processes0, 1, 2, and 3, respectively.

For an audio frame periodicity of 60 ms, FIG. 11 illustrates three audioframes with 396 bits in a MAC PDU. Accordingly, two MAC PDUs may betransmitted in 80 ms, each MAC PDU in a different HARQ process, each ofwhich can retransmit a maximum of 10 times. In particular, audio framebundles 1121, 1122, and 1123 are transmitted using HARQ processes 0, 5,and 3, respectively.

Note that in FIGS. 9-11, more retransmissions may be possible forcertain configurations. For example, for audio frame periodicities of 40ms and 60 ms in FIGS. 8-10 as well as 20 ms in FIG. 11, moreretransmissions may be possible within the 80 ms budget by usingadditional HARQ processes. However, the larger bundles may use morepower and a larger network uplink grant (resource). Additionally, byavoiding using all of the HARQ processes, the device may be able tosleep more often and conserve battery power. Of course, where weakerradio conditions occur, these additional HARQ processes andretransmissions may be used to ensure proper payload delivery.

In some embodiments, in coverage area C, a normal configuration may beused, e.g., CDRX 40 ms, two audio frame bundling into one PDCP/RLC/MACPDU every 40 ms, the MAC PDU is transmitted on one HARQ process, RTT 8ms, normally retransmit 1-2 times, maximum number of retransmissionsfive times. With the device's (e.g., the accessory device 107 and/or theUE 106) measurement reports assistance, the network may enable 4-TTI-Bwhen it detects the device enters coverage area B. The device maynegotiate with the network to downgrade the audio codec to AMR-WB 6.6kbps and use a 4-TTI-B configuration, e.g., CDRX 40 ms, two audio framebundling into one PDCP/RLC/MAC PDU every 40 ms, then MAC PDU istransmitted on one HARQ process, each transmission is 4-TTI bundling,RTT 16 ms, normally retransmit 1-2 times, maximum number ofretransmission three times.

However, in some embodiments, after the device enters cell coverage areaB, if 4-TTI-B is not supported by the network, if the number of HARQretransmissions increases to more than three and if the second audioframe arrives before first audio frame has been acknowledged, the secondaudio frame should use an unused HARQ process instead of overriding acurrently used HARQ process, which may allow for two HARQ processesbeing active in transmission.

If any one of the HARQ retransmission counts increases to five, and fiveis the max number configured by the network, which may be typical, thedevice may transmit the audio frame again as a new MAC PDU on thecurrently used HARQ process, which may enable another maximum fiveretransmissions per HARQ process.

After the device enters coverage area A, the number of 4-TTI-Bretransmissions may increase to more than three times. When the secondbundle of two audio frames arrives before the first bundle has beenacknowledged, the second bundle should use an unused HARQ processinstead of overriding a currently used HARQ process, so two HARQprocesses are active in transmission. If any of the HARQ processes'number of retransmissions reaches five, and this situation persists fora certain period of time, the device should switch to one audio framebundle per 20 ms stage.

If 4-TTI-B is not supported by the network and if any of the HARQprocesses' number of retransmissions reaches 10 and the situationpersists for a certain period of time, the device may switch to oneaudio frame bundle per 20 ms stage.

If there is one audio frame bundle per 20 ms stage, one audio frame maybe encapsulated into one MAC PDU per 20 ms and the MAC PDU may betransmitted on one HARQ process. Each transmission may use 4-TTIbundling, RTT 16 ms, and up to five retransmissions. When a new audioframe is received per 20 ms before the current used HARQ processes areacknowledged, an unused HARQ process may be used instead of overriding acurrently used HARQ process until no unused HARQ process is available.Eventually, all four HARQ processes can be actively used, and the devicemay be continuously transmitting over the 80 ms period.

If 4-TTI-B is not supported by the network, each HARQ transmission maybe set to 1-TTI, RTT 8 ms, with up to five retransmissions. When a newaudio frame is received per 20 ms before used HARQ processes areacknowledged, an unused HARQ process may be used instead of overriding acurrently used HARQ process until no unused HARQ process is available.

If any one of the HARQ retransmission counts increases to five, and fiveis the maximum typically configured by the network, the device maytransmit the audio frame again as a new MAC PDU on the currently usedHARQ process. This may enable another 5 retransmissions per HARQprocess. If any one of the HARQ retransmission total counts increases to10, and five is the maximum typically configured by the network, thedevice may transmit the audio frame again as a new MAC PDU on an unusedHARQ process, which may enable another 10 retransmissions per HARQprocess. Eventually all eight HARQ processes can be actively used forfour audio frames, each audio frame occupying two HARQ processes.

FIG. 12—Example Simplified Accessory Device with Battery Unit

FIG. 12 is a simplified block diagram of accessory device 107, accordingto some embodiments. In the illustrated embodiment, accessory device 107includes a battery unit 1210, baseband circuitry 1220, voltage monitor1250, and exemplary non-radio components (speaker 1230, heart ratemonitor 1240, and display 360 in the illustrated embodiment). Otherelements of FIG. 12 may correspond to similarly numbered elements ofFIG. 3, in some embodiments.

In some embodiments, battery unit 1210 includes one or more batteriesconfigured to power device 107. In some embodiments, battery unit 1210is configured to provide battery output voltage level information tovarious elements of device 107. In some embodiments, the illustratedvoltage monitor 1250 includes circuitry configured to determine voltagelevel information for the battery unit 1210. The one or more batteriesare rechargeable in some embodiments.

In some embodiments, battery unit 1210 is able to support multiplecomponents of device 107 in full operational mode for only a shortperiod of time, especially when RF transmission is performed at peaktransmission power. In some operational situations, the battery outputvoltage may drop below a threshold voltage for short periods. If thishappens frequently, the one or more batteries may burn out and no longerfunction correctly. Therefore, reduction in the frequency of occurrenceof such low-voltage intervals while maintaining functionality of device107 (e.g., not dropping voice calls) may be desired.

Two techniques for dealing with limited RF capabilities in device 107include reducing VoLTE payload size and increasing the number oftransmissions for each VoLTE payload (e.g., using TTI-B (transmissiontime interval bundling) and/or increasing the number of times TTIbundles are transmitted).

As discussed above, there may be three general methods for reducingVoLTE payload size. A first method involves reducing the audio codecrate. A second method involves audio bundle splitting (e.g., asdiscussed with reference to FIG. 6). A third method involves using RLCsegmentation.

Also, increasing the number of transmissions for each VoLTE payload mayincrease the energy per bit and increase communication performance. Insome embodiments, the number of transmissions for a given HARQ processis limited. For example, if the VoLTE transmission period is 20 ms,there may be a maximum of two TTI bundles for a given HARQ process; ifthe VoLTE transmission period is 40 ms, there may be a maximum of threeTTI bundles for a given HARQ process; and if the VoLTE transmissionperiod is 60 ms, there may be a maximum of four TTI bundles for a givenHARQ process. Thus, to increase the maximum number of transmissions in atransmission period above these limits, multiple parallel HARQ processesmay be needed. Further, under typical operating conditions, the numberof HARQ processes needed may be greater than indicated by the examplesabove, e.g., because the number of maximum transmissions that canactually be performed is typically smaller than the provided idealvalues.

In some embodiments, if the number of parallel HARQ processes isinsufficient, audio frames in the PDCP buffer may have to be discardedonce a timer expires (e.g., after 100 ms in some embodiments) which maycause an increase in frame error rate. A frame error rate of 1% or lessmay be needed for good VoLTE call quality. Further, acceptable VoLTEcall quality may require a mouth-to-ear total delay of less than 270 ms,which may be effected by the number of transmissions.

Increasing the number of parallel HARQ processes, however, may increasethe average transmission duty cycle, which may draw more power frombattery unit 1210 and cause the output voltage to dip below theacceptable voltage level.

FIGS. 13A-13B—Exemplary Technique for TX Blanking Based on Battery Level

FIG. 13A is a flowchart diagram illustrating a method for stoppingscheduled transmissions for audio frame transmission based on batteryinformation. The method may be performed by an accessory device (such asaccessory device 107) and/or a UE device (such as UE 106), e.g., usingthe systems and methods discussed above. More generally, the methodshown in FIG. 13A may be used in conjunction with any of the systems ordevices discussed herein, among other devices. In various embodiments,some of the method elements shown may be performed concurrently, in adifferent order than shown, or may be omitted. Note also that additionalmethod elements may also be performed as desired. The method may beperformed as follows.

At 1302, an indication is received that battery output voltage is belowa threshold. In some embodiments, battery unit 1210 is configured toprovide this indication to baseband circuitry 1220. The low batteryoutput may be caused by cellular transmissions at high power while otherelements of device 107 are operating in a full operational mode, forexample, among other potential causes. Note that while VoLTE isdiscussed with reference to some embodiments, the disclosed techniquesmay be used in various embodiments with any appropriate packet-switchedvoice communications technology. VoLTE is discussed for illustratingpurposes and is not intended to limit the scope of the presentdisclosure.

At 1304, device 107 stops baseband transmissions until the indication isreleased (e.g., until the battery level is above the threshold). In someembodiments, the transmissions may be stopped even though they have beenscheduled (e.g., even though the network has provided grants for thetransmissions). In some embodiments, different battery level thresholdsmay be used to stop and start baseband transmissions while in otherembodiments the same threshold may be used. Because the battery-lowcondition may typically be short (e.g., 1 ms and rarely exceeding 5 ms),in embodiments in which HARQ and/or TTI-B are used, stopping thetransmissions may not prevent successful transmission of an audio frame(e.g., one or more TTI-B transmissions may already have been sent or maybe sent after the blanking interval and may be decoded successfully bythe network). In other situations, transmission of audio data may needto be rescheduled, e.g., as discussed below with reference to FIG. 13B.

In some embodiments, device 107 is configured to determine and storeinformation indicating the frequency of this indication, whichtransmissions are blanked, the number of stopped transmissions for eachVoLTE payload or audio frame, and the HARQ process(es) of blankedtransmissions.

FIG. 13B is a flowchart diagram illustrating a method for re-schedulingtransmission of audio frames based on stopped transmissions. The methodmay be performed by an accessory device (such as accessory device 107)and/or a UE device (such as UE 106), e.g., using the systems and methodsdiscussed above. More generally, the method shown in FIG. 13B may beused in conjunction with any of the systems or devices discussed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Note also that additional method elements may also beperformed as desired. The method may be performed as follows.

At 1312, device 107 determines the number of stopped transmissions for aVoLTE payload (e.g., as discussed with reference to 1304 above).

At 1314, if the number of stopped transmissions for the VoLTE payload isabove a threshold value, the original audio frame is placed back in thePDCP buffer for eventual re-transmission. Device 107 may abort thecurrent transmission of the VoLTE payload using the current HARQ processin conjunction with placing the payload back in the PDCP buffer. Theframe may subsequently be re-transmitted from the PDCP buffer out ofreal-time protocol (RTP) order, but this may be resolved by the network,e.g., using an audio jitter buffer. In some embodiments, putting audioframes back in the buffer may eventually cause frames to be dropped,e.g., due to a timer expiration for the PDCP buffer. An exemplary timerinterval is 100 ms.

In some embodiments, if the number of stopped transmissions for theVoLTE payload is less than the threshold value, the blanking isprocessed as a normal transmission failure (e.g., handled similarly to afailure to pass a cyclic redundancy check) rather than re-scheduling theaudio frame.

In some embodiments, device 107 is configured to measure and storeinformation indicating one or more of: average number of transmissionsper VoLTE payload, block error rate (BLER), the number of audio framespending in the PDCP buffer, and/or the discard rate from the PDCP bufferdue to timer expiration(s).

FIG. 14—Exemplary Reduction of Battery Usage During Talking State

Normal speech patterns typically include roughly 40% talking, 20%silence, and 40% listening. Also, a normal burst of speech typicallylasts from 500 ms to 2 seconds. In some embodiments, device 107 isconfigured to determine a speech mode, e.g., based on the contents ofaudio frames being transmitted. In some embodiments, device 107 isconfigured to perform one or more power reduction actions when in atalking state, e.g., based on battery output level.

FIG. 14 is a flowchart diagram illustrating a method for reducingbattery usage during a talking state, according to some embodiments. Themethod may be performed by an accessory device (such as accessory device107) and/or a UE device (such as UE 106), e.g., using the systems andmethods discussed above. More generally, the method shown in FIG. 14 maybe used in conjunction with any of the systems or devices discussedherein, among other devices. In various embodiments, some of the methodelements shown may be performed concurrently, in a different order thanshown, or may be omitted. Note also that additional method elements mayalso be performed as desired. The method may be performed as follows.

At 1402, device 107 (e.g., using baseband circuitry 1220) determines acurrent speech state to be a talking state. In some embodiments,baseband circuitry 1220 makes this determination by detecting whetherone or more audio frames pending transmission are silence frames or realaudio frames. In the illustrated embodiment, device 107 furtherdetermines that the battery low voltage indicator is occurring at afrequency that is above a threshold frequency, which may mean thatrunning out of battery power and/or damage to the battery may beimminent.

At 1404, device 107 requests other components (e.g., other than cellulartransmission components) to reduce battery usage. In some embodiments,baseband circuitry 1220 is configured to send a global request tocomponents of device 107. In some embodiments, baseband circuitry 1220is configured to send requests to individual components. In someembodiments, the components may be configured to decide whether toaccede to the request based on current operating conditions.Non-limiting examples of reductions in battery usage include: reducingthe volume of speaker 1230, reducing the measuring frequency of heartrate monitor 1240, reducing the brightness of display 360, altering apower mode of processor(s) 302, disabling other wireless communications(e.g., WiFi and/or Bluetooth communications), etc.

FIG. 15—Dynamic Adjustment of Parallel HARQ Processes

FIG. 15 is a flowchart diagram illustrating a method for dynamicallyadjusting the number of HARQ processes used in parallel. The method maybe performed by an accessory device (such as accessory device 107)and/or a UE device (such as UE 106), e.g., using the systems and methodsdiscussed above. More generally, the method shown in FIG. 15 may be usedin conjunction with any of the systems or devices discussed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Note also that additional method elements may also beperformed as desired. The method may be performed as follows.

At 1502, device 107 detects that a current speech state is a talkingstate. At 1504, device 107 determines whether the battery low voltageindicator frequency is above a threshold. The frequency may be averagedover a time interval of some pre-determined length. In some embodiments,the threshold is the same threshold as discussed above with reference toelement 1402 of FIG. 14. If the frequency is above the threshold, flowproceeds to 1512.

At 1512, device 107 reduces the number of HARQ processes used inparallel. For example, baseband circuitry 1220 may reduce the number ofHARQ processes from 4 to 3, from 4 to 2, from 3 to 2, etc. In someembodiments, reducing the number of HARQ processes by one may reduce TXpower consumption by approximately 25%. Baseband circuitry 1220 maydetermine the HARQ process(es) to stop based on RTP sequence number(e.g., stopping the HARQ process with the largest RTP number may preventthe most-recently-scheduled transmission but allow older transmissionsto proceed). Baseband circuitry 1220 may place the audio frameassociated with the stopped HARQ process back in the PDCP buffer basedon its RTP sequence number. When a HARQ sequence is stopped by device107, it may not send any transmissions even though the network may haveassigned an UL grant to the process, e.g., with a re-transmission grant.In some embodiments, if the HARQ process is being used to transmit oneRLC segment of an audio bundle, baseband circuitry 1220 is configured toalso stop the HARQ process being used to transmit the other RLC segmentof the same audio bundle.

At 1514, device 107 indicates the reduction in the number of HARQprocesses to the network. This may prevent the network from providing agreater number of grants than the current number of HARQ processes canutilize. To maintain the number of HARQ processes being used, device 107may send a buffer status report (BSR) that includes the total number ofbytes corresponding to audio frames that are enough to keep the newnumber of HARQ processes busy. This size may vary in differentsituations and embodiments. The following non-limiting examples areprovided for situations in which C-DRX is configured to use 40 msperiods. In other situations, similar techniques may be used todetermine BSR information, as appropriate.

In some embodiments, the following techniques are used when two HARQprocesses are used in parallel. If the grant from the network is for 176bits, the BSR is generated to have a size of two audio frames and RLCsegmentation is used so that the two-audio-frame bundle with a size of328 bits becomes two segments, each of 176 bits. If the grant from thenetwork is 208 bits, the BSR is generated to have a size of two audioframes and audio-splitting is used (e.g., as described above withreference to FIGS. 5-6) and the two-audio-frame bundle of size 328 bitsbecomes two audio frames, each with 208 bits. If the grant from thenetwork is 328 bits, the BSR is generated to have a size of four audioframes with two two-audio-frame bundles, where each bundle has a size of328 bits and uses one HARQ process.

In some embodiments, the following techniques are used when three HARQprocesses are used in parallel. If the grant from the network is 328bits, the BSR is generated to have a size of three two-audio-framebundles, where each bundle size is 328 bits and each two-audio-framebundle uses one HARQ process. If the grant from the network is 176 bitsfor RLC segments or 208 bits for audio split, the BSR is generated tohave a size of three segments.

In some embodiments, the following techniques are used when four HARQprocesses are used in parallel. If the grant from the network is 328bits, the BSR is generated to have a size of four two-audio-framebundles, each having 328 bits and using one HARQ process. If the grantis 176 bits for RLC segments or 208 bits for audio split, the BSR isgenerated to have a size of four segments, or two two-audio-framebundles, such that each segment uses one HARQ process.

As shown, if the reduction in HARQ processes does not cause the batterylow voltage indicator frequency to fall below the threshold, blocks 1512and 1514 may be performed one or more additional times (further reducingthe number of HARQ processes) until the frequency is below thethreshold.

In some embodiments, based on the number of HARQ processes being used,the number of frames pending in the PDCP buffer, the PDCP drop rate, theBLER, and/or the number of transmissions per audio bundle, basebandcircuitry 1220 may be configured to drop the VoLTE call, e.g., if itdetermines that acceptable call quality can only be maintained (e.g., 1%frame error rate or less) by keeping the battery low voltage indicatorfrequency above the threshold.

If the battery low voltage indicator frequency is below the threshold at1504, flow proceeds to 1522. At 1522, device 107 measures the averageframes pending in the PDCP buffer, the PDCP drop rate, the averagenumber of transmissions per audio bundle, and/or the BLER.

At 1524, based on the information determined at 1522, if additional HARQprocesses are needed to maintain call quality, then the number of HARQprocesses used in parallel is increased. In some embodiments, device 107is configured to indicate the increase to the network, e.g., asdescribed above with reference to 1514, but for an increase instead of areduction. This may ensure that the network provides grants to utilizethe increased number of HARQ processes.

In some embodiments, repeated performance of the two different branchesfrom 1504 may create a closed control loop in which the number of HARQprocesses is increased or reduced to create a stable system withefficient battery power usage, in most operating conditions.

FIG. 16—Non-Talking States

FIG. 16 is a flowchart diagram illustrating a method for operating innon-talking speech states (e.g., listening and silence states),according to some embodiments. The method may be performed by anaccessory device (such as accessory device 107) and/or a UE device (suchas UE 106), e.g., using the systems and methods discussed above. Moregenerally, the method shown in FIG. 16 may be used in conjunction withany of the systems or devices discussed herein, among other devices. Invarious embodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted. Notealso that additional method elements may also be performed as desired.The method may be performed as follows.

At 1602, device 107 detects that the device is in a non-talking state.Baseband circuitry 1220 may detect a non-talking state based on thecontents of scheduled audio frames and/or the lack of audio frames, insome embodiments.

At 1604, baseband circuitry 1220 indicates to other components that theycan increase battery usage. In some embodiments, baseband circuitry 1220is configured to send a global indication to components of device 107.In some embodiments, baseband circuitry 1220 is configured to sendindications to individual components. Non-limiting examples of increasesin battery usage include: increasing the volume of speaker 1230,increasing the measuring frequency of heart rate monitor 1240,increasing the brightness of display 360, altering a power mode ofprocessor(s) 302, enabling other wireless communications (e.g.,Bluetooth communications), etc.

In some embodiments, two or more of the methods of FIGS. 13-16 and/orportions thereof may be used in combination to maintain a stable systemin which call quality is efficiently maintained without battery damage.

Various Embodiments

The following paragraphs describe exemplary embodiments of the presentdisclosure.

One set of embodiments may include a mobile device, comprising: at leastone antenna for performing wireless communication; a first radio coupledto the at least one antenna, wherein the first radio is configured toperform cellular communication with a base station; one or moreprocessors coupled to the first radio, wherein the one or moreprocessors and the first radio are configured to perform wirelesscommunications using the at least one antenna; wherein the mobile deviceis configured to: communicate with a base station, wherein thecommunication comprises a real-time IP session, wherein at a first timeduring the real-time IP session, communication between the mobile deviceand the base station may have a first performance metric and the mobiledevice may implement a first frame transmission scheme; determine acurrent performance metric for communication of the real-time IPsession; and based on the current performance metric, modify the firstframe transmission scheme of the real-time IP session.

According to some embodiments, the first performance metric and thecurrent performance metric comprise one or more of block error rate(BLER) or received signal strength indication (RSSI).

According to some embodiments, the first frame transmission schemecomprises using a first audio codec rate, wherein the secondtransmission scheme comprises using a second audio codec rate lower thanthe first audio codec rate.

According to some embodiments, the first frame transmission schemecomprises using a first number of retransmissions, wherein the secondtransmission scheme comprises using a second number of retransmissionshigher than the first number of retransmissions.

According to some embodiments, the first frame transmission schemecomprises using a first number of HARQ processes, wherein the secondtransmission scheme comprises using a second number of HARQ processeshigher than the first number of HARQ processes.

According to some embodiments, the first frame transmission schemecomprises bundling a first number of frames, wherein the secondtransmission scheme comprises bundling a second number of framesdifferent than the first number of frames.

According to some embodiments, the first frame transmission schemecomprises using a first MAC PDU size, wherein the second transmissionscheme comprises using a second MAC PDU size different than the firstMAC PDU size.

According to some embodiments, said determining and said modifying isperformed a plurality of times throughout the IP session.

According to some embodiments, the IP session comprises a VoLTE session.

According to some embodiments, the mobile device is a smart watch.

According to some embodiments, the mobile device is an accessory device,wherein the mobile device further comprises: a second radio coupled tothe at least one antenna, wherein the second radio is configured toperform short range communication with a companion device.

One set of embodiments may include a mobile device, comprising: at leastone antenna for performing wireless communication; a first radio coupledto the at least one antenna, wherein the first radio is configured toperform cellular communication with a base station; one or moreprocessors coupled to the first radio, wherein the one or moreprocessors and the first radio are configured to perform wirelesscommunications using the at least one antenna; wherein the mobile deviceis configured to: communicate with a base station, wherein thecommunication comprises a voice over IP (VoIP) session; determine anuplink grant size for the VoIP session; compare the uplink grant size toan audio bundle size of an audio configuration used for the VoIPsession; in response to the uplink grant size being less than the audiobundle size, modify the audio configuration to reduce the audio bundlesize to less than or equal to the uplink grant size.

According to some embodiments, modifying the audio configurationcomprises reducing the number of audio frames per audio bundle.

According to some embodiments, reducing the number of audio frames peraudio bundle comprises reducing the number of audio frames per audiobundle to one.

According to some embodiments, modifying the audio configurationcomprises reducing an audio codec rate.

One set of embodiments may include an accessory device, comprising: atleast one antenna for performing wireless communication; a first radiocoupled to the at least one antenna, wherein the first radio isconfigured to perform cellular communication with a base station; asecond radio coupled to the at least one antenna, wherein the secondradio is configured to perform short range communication with acompanion device; one or more processors coupled to the first and secondradios, wherein the one or more processors and the first and secondradios are configured to perform wireless communications using the atleast one antenna; wherein the accessory device is configured to:perform an IP session with a base station, wherein at a first time,communication between the accessory device and the base station may havea first performance metric and the accessory device may implement afirst frame transmission scheme; determine a current performance metric;based on the current performance metric, modify the first frametransmission scheme.

According to some embodiments, the first performance metric and thecurrent performance metric comprise one or more of block error rate(BLER) or received signal strength indication (RSSI).

According to some embodiments, the first frame transmission schemecomprises using a first audio codec rate, wherein the secondtransmission scheme comprises using a second audio codec rate lower thanthe first audio codec rate.

According to some embodiments, the first frame transmission schemecomprises using a first number of retransmissions, wherein the secondtransmission scheme comprises using a second number of retransmissionshigher than the first number of retransmissions.

According to some embodiments, the first frame transmission schemecomprises using a first number of HARQ processes, wherein the secondtransmission scheme comprises using a second number of HARQ processeshigher than the first number of HARQ processes.

According to some embodiments, the first frame transmission schemecomprises bundling a first number of frames, wherein the secondtransmission scheme comprises bundling a second number of framesdifferent than the first number of frames.

According to some embodiments, the first frame transmission schemecomprises using a first MAC PDU size, wherein the second transmissionscheme comprises using a second MAC PDU size different than the firstMAC PDU size.

According to some embodiments, said determining and said modifying isperformed a plurality of times throughout the IP session.

One set of embodiments may include a mobile device, comprising: at leastone antenna for performing wireless communication, a first radio coupledto the at least one antenna, wherein the first radio is configured toperform cellular communication with a base station, and one or moreprocessors coupled to the first radio, wherein the one or moreprocessors and the first radio are configured to perform wirelesscommunications using the at least one antenna.

According to some embodiments, the mobile device is configured tocommunicate with a base station, wherein the communication comprises areal-time IP session, wherein at a first time during the real-time IPsession, communication between the mobile device and the base stationmay have a first performance metric and the mobile device may implementa first frame transmission scheme. According to some embodiments, themobile device is configured to determine a current performance metricfor communication of the real-time IP session and, based on the currentperformance metric, modify the first frame transmission scheme of thereal-time IP session.

According to some embodiments, the first performance metric and thecurrent performance metric comprise one or more of a block error rate(BLER) or received signal strength indication (RSSI).

According to some embodiments, the first frame transmission schemecomprises using a first audio codec rate, and wherein the secondtransmission scheme comprises using a second audio codec rate lower thanthe first audio codec rate.

According to some embodiments, the first frame transmission schemecomprises using a first number of retransmissions, and wherein thesecond transmission scheme comprises using a second number ofretransmissions higher than the first number of retransmissions.

According to some embodiments, the first frame transmission schemecomprises using a first number of HARQ processes, and wherein the secondtransmission scheme comprises using a second number of HARQ processeshigher than the first number of HARQ processes.

According to some embodiments, the first frame transmission schemecomprises bundling a first number of frames, and wherein the secondtransmission scheme comprises bundling a second number of framesdifferent than the first number of frames.

According to some embodiments, the first frame transmission schemecomprises using a first MAC PDU size, and wherein the secondtransmission scheme comprises using a second MAC PDU size different thanthe first MAC PDU size.

According to some embodiments, said determining and said modifying isperformed a plurality of times throughout the IP session.

According to some embodiments, the real time IP session comprises aVoLTE session.

According to some embodiments, the mobile device is an accessory device,wherein the mobile device further comprises: a second radio coupled tothe at least one antenna, wherein the second radio is configured toperform short range communication with a companion device.

One set of embodiments may include a mobile device, comprising: at leastone antenna for performing wireless communication, a first radio coupledto the at least one antenna, wherein the first radio is configured toperform cellular communication with a base station, and one or moreprocessors coupled to the first radio, wherein the one or moreprocessors and the first radio are configured to perform wirelesscommunications using the at least one antenna.

According to some embodiments, the mobile device is configured to:communicate with a base station, wherein the communication comprises avoice over IP (VoIP) session, determine an uplink grant size for theVoIP session, compare the uplink grant size to an audio bundle size ofan audio configuration used for the VoIP session, and, in response tothe uplink grant size being less than the audio bundle size, modify theaudio configuration to reduce the audio bundle size to less than orequal to the uplink grant size.

According to some embodiments, modifying the audio configurationcomprises reducing the number of audio frames per audio bundle.

According to some embodiments, reducing the number of audio frames peraudio bundle comprises reducing the number of audio frames per audiobundle to one.

According to some embodiments, modifying the audio configurationcomprises reducing an audio codec rate.

In one set of embodiments, a mobile device may be configured to: inresponse to detecting that a voltage corresponding to battery output isbelow a particular threshold, preventing an upcoming scheduled wirelesstransmission until the voltage returns to above the particularthreshold.

According to some embodiments, the upcoming scheduled transmission isone of multiple transmissions for an audio frame based on HARQ and TTI-Btransmission of the audio frame.

According to some embodiments, the mobile device is further configuredto: determine and store information indicating the audio frame and aHARQ process corresponding to the upcoming scheduled transmission.

According to some embodiments, the mobile device is configured to, inresponse to determining that a number of stopped upcoming scheduledtransmissions for the audio frame exceeds a threshold number oftransmissions, put the audio frame back into a Packet Data ConvergenceProtocol (PDCP) buffer from which the audio frame was retrieved fortransmission.

According to some embodiments, the mobile device is further configuredto determine and store at least one of: an average number oftransmissions for each of a plurality of audio frames over a timeinterval, a number of audio frames pending in a PDCP buffer, a number ofaudio frames discarded from the PDCP buffer, or a block error rate(BLER) for the plurality of audio frames.

According to some embodiments, the audio frame is a voice over LTE(VoLTE) frame.

According to some embodiments, the mobile device is configured to stopall cellular transmissions from the mobile device until the voltagecorresponding to the battery output is above a threshold value.

According to some embodiments, the mobile device is configured todetermine: the length of a time interval during which the voltagecorresponding to the battery output is below the particular thresholdand the frequency at which the voltage corresponding to the batteryoutput drops below the particular threshold.

In one set of embodiments, a mobile device may be configured to:determine that the mobile device is in a talking state, determine that avoltage corresponding to battery output is dropping below a thresholdvalue at greater than a threshold frequency, and perform a powerreduction action in response to the determination that the mobile deviceis in a talking state and that the voltage is dropping below a thresholdvalue at greater than the threshold frequency.

According to some embodiments, the power reduction action includesreducing power consumption by one or more non-radio components of themobile device.

According to some embodiments, to reduce power consumption by othercomponents of the mobile device, the mobile device is configured toperform one or more of: reduce a heart rate monitor measuring frequency,reduce a screen brightness, reduce an audio volume, alter a processorpower mode, or disable short-range wireless transmissions.

According to some embodiments, the power reduction action includesreducing a number of HARQ processes used in parallel by the mobiledevice to generate transmissions for audio frames.

According to some embodiments, the mobile device is configured to selecta HARQ process to stop when reducing the number of HARQ processes basedon a real-time protocol (RTP) sequence number of a packet beingprocessed by the HARQ process.

According to some embodiments, the mobile device is configured to stopmultiple HARQ processes that are being used to process different radiolink control (RLC) segments of the same audio payload.

According to some embodiments, the mobile device is configured toincrease a number of HARQ processes used in parallel by the mobiledevice to generate transmission for audio frames in response todetermining that the voltage corresponding to battery output is droppingbelow a threshold value at a frequency that is lower than the thresholdfrequency.

According to some embodiments, the mobile device is configured totransmit a buffer status report (BSR) that indicates a number of HARQprocesses used in parallel by the mobile device after the powerreduction action.

According to some embodiments, the mobile device is configured to drop acall in response to at least one of the following conditions afterreducing the number of HARQ processes: a frame error rate above aparticular threshold, or an audio frame drop rate for a Packet DataConvergence Protocol (PDCP) buffer above a particular threshold.

According to some embodiments, the mobile device is configured todetermine that it is in a talking state based on the contents of audioframes being processed by the mobile device.

According to some embodiments, the mobile device is configured to, inresponse to determining that the mobile device is not in a talkingstate, increase power provided to one or more non-radio components ofthe mobile device.

One set of embodiments may include a method corresponding to the mobiledevice discussed above.

One set of embodiments may include a non-transitory computer accessiblememory medium storing program instructions corresponding to theaccessory device discussed above.

One set of embodiments may include a computer program comprisinginstructions corresponding to the accessory device discussed above.

One set of embodiments may include an apparatus comprising means forperforming methods corresponding to the accessory device discussedabove.

One set of embodiments may include a method that includes any action orcombination of actions as substantially described herein in the DetailedDescription.

One set of embodiments may include a method as substantially describedherein with reference to each or any combination of the Figures or withreference to each or any combination of paragraphs in the DetailedDescription.

One set of embodiments may include a wireless device configured toperform any action or combination of actions as substantially describedherein in the Detailed Description.

One set of embodiments may include a wireless device that includes anycomponent or combination of components as described herein in theDetailed Description as included in a wireless device.

One set of embodiments may include a non-volatile computer-readablemedium that stores instructions that, when executed, cause theperformance of any action or combination of actions as substantiallydescribed herein in the Detailed Description.

One set of embodiments may include an integrated circuit configured toperform any action or combination of actions as substantially describedherein in the Detailed Description.

Embodiments of the present disclosure may be realized in any of variousforms. For example some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106 or accessory device 107)may be configured to include a processor (or a set of processors) and amemory medium, where the memory medium stores program instructions,where the processor is configured to read and execute the programinstructions from the memory medium, where the program instructions areexecutable to implement a method, e.g., any of the various methodembodiments described herein (or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets). Thedevice may be realized in any of various forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. An apparatus, comprising: one or more processingelements; and one or more memories having program instructions storedthereon that are executable by the one or more processing elements to:wirelessly communicate with a base station for a cell, wherein thecommunication includes a voice or video session, wherein at a first timeduring the voice or video session, communication between the apparatusand the base station uses a first retransmission parameter for an uplinkcommunication; detect a weak cell condition associated with the cell;and based on the weak cell condition, communicate with the base stationto use a second retransmission parameter for uplink communications forthe voice or video session, wherein the second retransmission parameterextends uplink delay budget relative to the first retransmissionparameter.
 2. The apparatus of claim 1, wherein the secondretransmission parameter includes enabling transmission time interval(TTI) bundling, wherein TTI bundling uses a number of retransmissionsassociated with a HARQ process within a TTI bundle size, wherein thefirst retransmission parameter does not enable TTI-bundling.
 3. Theapparatus of claim 1, wherein the second retransmission parameter has areduced codec rate relative to the first retransmission parameter. 4.The apparatus of claim 1, wherein the first retransmission parameterspecifies using a first number of repetitions and wherein the secondretransmission parameter specifies using a second number of repetitionsthat is greater than the first number of repetitions.
 5. The apparatusof claim 1, wherein the communication with the base station includesindicating the weak cell condition to the base station.
 6. The apparatusof claim 1, wherein the weak cell condition corresponds to quality ofthe voice or video session.
 7. The apparatus of claim 1, wherein theweak cell condition corresponds to radio conditions associated with cellcoverage.
 8. The apparatus of claim 1, wherein the apparatus is a mobiledevice that further comprises: one or more radios; and one or moreantennas.
 9. A non-transitory computer-readable medium havinginstructions stored thereon that are executable by a mobile computingdevice to perform operations comprising: wirelessly communicating with abase station for a cell, wherein the communication includes a voice orvideo session, wherein at a first time during the voice or videosession, communication between the computing device and the base stationuses a first retransmission parameter for an uplink communication;detecting a weak cell condition associated with the cell; and based onthe weak cell condition, communicating with the base station to use asecond retransmission parameter for uplink communications for the voiceor video session, wherein the second retransmission parameter extendsuplink delay budget relative to the first retransmission parameter. 10.The non-transitory computer-readable medium of claim 9, wherein thesecond retransmission parameter includes enabling transmission timeinterval (TTI) bundling, wherein TTI bundling uses a number ofretransmissions associated with a HARQ process within a TTI bundle size,wherein the first retransmission parameter does not enable TTI-bundling.11. The non-transitory computer-readable medium of claim 9, wherein thefirst retransmission parameter specifies using a first number ofrepetitions and wherein the second retransmission parameter specifiesusing a second number of repetitions that is greater than the firstnumber of repetitions.
 12. The non-transitory computer-readable mediumof claim 9, wherein the communication with the base station includesindicating the weak cell condition to the base station.
 13. Thenon-transitory computer-readable medium of claim 9, wherein the weakcell condition corresponds to one or more of: quality of the voice orvideo session; or radio conditions associated with cell coverage.
 14. Amethod, comprising: wirelessly communicating, by a base station for acell, with a mobile device, wherein the communication includes a voiceor video session, wherein at a first time during the voice or videosession, the communicating uses a first retransmission parameter for anuplink communication; and wirelessly communicating, by the base stationwith the mobile device, to use a second retransmission parameter foruplink communications for the voice or video session, wherein the secondretransmission parameter extends uplink delay budget relative to thefirst retransmission parameter, wherein the use of the secondretransmission parameter is based on detection of a weak cell conditionassociated with the cell.
 15. The method of claim 14, wherein the secondretransmission parameter includes enabling transmission time interval(TTI) bundling, wherein TTI bundling uses a number of retransmissionsassociated with a HARQ process within a TTI bundle size, wherein thefirst retransmission parameter does not enable TTI-bundling.
 16. Themethod of claim 14, wherein the second retransmission parameter has areduced codec rate relative to the first retransmission parameter. 17.The method of claim 16, wherein the weak cell condition corresponds toone or more of: quality of the voice or video session; or radioconditions associated with cell coverage.
 18. The method of claim 14,wherein the first retransmission parameter specifies using a firstnumber of repetitions and wherein the second retransmission parameterspecifies using a second number of repetitions that is greater than thefirst number of repetitions.
 19. The method of claim 14, wherein thewirelessly communicating includes receiving information from the mobiledevice that indicates the weak cell condition.
 20. The method of claim14, wherein the voice or video session includes voice over long termevolution (VoLTE) communication.